Dead latch mechanism



April 7, 1956 F. J. RUSSELL DEAD LATCH MECHANISM Filed June 18, 1954 2 Sheets-Sheet l PEN? , mm L LR H Y "am a? wm m RN R T 0 BR E E0" R WW F V/ 5 J g a 9 2 H M 6 2% 2 Sheets-Sheet 2 Filed June 18, 1954 nigq. 3.

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Application June 18, 1954, Serial No.'437, 605

1 Claim. or. 292-469) Theinverition relates to locking devices and has particular reference to a latch mechanismrequippe'd with ad'ead 'unlockedrposition by unauthorized persons. ",Indeadlock prompted urge to emphasize security. Because of the growing tendency to -r'educ'ethe size of casings and St s P s 0 2,742,310 Patented Apr. 17, 1956 panying :drawings.

In thedrawings: Figure '1 .is' a horizontal view of the device asinstalled in a door partly broken away to show the location of the dead bolt mechanism.

Figure 2 is a longitudinal sectional view of the device with parts in the position occupied when the door isopen. Figure 3 is a longitudinal sectional view takenon the line3-3 of Figure 2.

Figure4 is a longitudinal sectional view taken on the 1ine'4--'4 of Figure 2.

Figure "Sis a cross-sectional view taken on the line 5-5 of Figure 2.

Figure 6 is a cross-sectional view on the line 6-6 of Figure '3.

Figure 7, is a partial sectional view similar to Figure 2 but 'showin'g'the condition of the mechanism as it would be with a door closed. A

Figure8 is'a view similar to Figure 2 showingthe parts ,in thep'osition they would have as thelatch bolt is being j retracted' by rotation of the knob..

mg mechanisms the tendency has been heretofore tobuild h a'considerable ruggedness into the mechanism doubtless housings for cylinder lock setsand tubularlo'ckset's, dead 3 bolt mechanisms which 'have been constructed .injanf ,attempt to emphasizesecu'rity have been complicatedto a considerable degree andhave necessitated careful machining of close-fitting parts in order to make certain "thatthe dead bolt mechanism operates with the consistency and security expected. The design andco'nstruction thus em .,ployed'heretofore has invariably resulted in an expensive .construction which has made'the' retail price of look hard- ,ware of this type prohibitive economically for a "great many installations. i

It is accordingly among the objects of the invention to provide a new and improved latchmechan'ism which'incorporates a dead locking feature wherein the mechanismis simple, inexpensive, and at the same time reliablysecure.

Another object of the invention is to provide a new and improved latch mechanism featuring a dead boltimec'h'anism wherein an actuator spring for the deadbolt'mechanism is kept light in weight and separated from the'r'emainingportions of the latch mechanism so as to a'ssure positive and secure action of the dead bolt without adding to a f material extent to the cost of the mechanism fasa whole.

Still another object of the invention is to provide a .new and improved combined latch and dead latchde'vice simply and economically constructed but Withouts'acrifice of positive and secure action wherein spring means is adapted to provide tension of dilferent degreesjfor the dead therefore madeavailable for many types of installations which heretofore have not been able to be supplied by latch and dead bolt combinations available.

With these and other objects in. view, the invention con- Figure 9. is an exploded view showing the parts respect'ively of the latch bolt member and dead bolt member. .25.?

In'. ,the combined latch and dead bolt mechanism chosen for'the purpose of illustration there is shown an' outer fknob assembly 10 and an inner knob assembly 1 1'jsecured together by suitable connecting means 12 in a door 13. f A1spindle 14. extend s between the outer and inner knob assemblies. The door" is shown closed with respect to a door frame-15 provided with a strike plate 16 and ardoor mm 17. a

A cylindrical housing is has an inner wan 19 at the end 'which 'exends into. the .door 13. The outer end of "thecylindrical casing is open as indicated at 20. For' convenience theouter end of the housing is provided with afla'n'ge 21 adapted to overlie plate's22by means of which the housing is secured within a bore23 extending edgewise of thedoor 13. Thefbore 23 communicates with a transverse aperture 24 through which the spindle extends.

In the housing 18 is a latch bolt assembly reciprocatably "(mounted and consisting of a latch bolt head 27 having a (customary. tapered face 28 adapted to engage the strike plate.16. Attached to the head is a latch boltshaft 29,

-the latch bolt shaft being in the form of a flat plate intermediate opposite sides of the bolt. The .latch bolt shaft "hasa'rec't'angular opening 36 intermediate inner and outer ends. The inner end may be bifurcated as a structural convenience providing thereby legs 31 and 32 having a space 3 therebetween. The form of the latch bolt shaft is shownlto good advantage in Figure 9.

Giooperable with the latch bolt shaft 29 is an actuator plate '34 having a hooked portion 35 extending through the rectangular opening 30. At the inner .end of the actuator plate are lugs 36 against which a cam 37 is "the 'slo'tand space being adapted to admit a post 39 'comprising a portion of the connecting means 12.

A'-'relatively heavy coiled compression spring 40 is biased between the inside of the inner wall 19 and a she'1f'41 which is part of the actuator plate 34. The

sprin'g 40resists'rotation of the operating assemblies and serves to-return the actuator plate to anouter position "after the latch bolt assembly has been withdrawn.

.Thezilatch bolt head 27 and latch" bolt shaft 29 are adapted to move independently of the actuator plate 34 southat the head can shift as it strikes the strike plate without the necessity of the operating assemblies rotating.

arsen c relatively lighter compression spring '42 biasedbetwe'en i an inside face 43 of the head and the shelf 41 on the side opposite from the spring 40.

A dead bolt mechanism comprisesessentially a dead bolt head 50 which lies adjacent the long side'of the latch bolt head 27. At the inner end of the dead bolt head 50, as seen to good advantage'in Figure 9, are

slots 51 adapted to receive wings 52 extending transversely at the outer end of adead bolt shaft 53. The dead bolt shaft is also in the form of a flat plate also bifurcated as a structural convenience toward its inner end to provide legs 54 and 55 having a space 56 therebetween. Hooks 57 at the inner ends, of the legs 54 and 55 extend inwardly into the space 56. Raised portions 58 and 59 are located intermediate outer and inner ends of the legs and form operating elements of the dead bolt mechanism. a

A dead locking blocker 60, illustrated to good advantage in Figure 9, has an inner end portion 61 terminating in lugs 62, the lugs being adapted to extend through appropriate apertures in the inner end wall 19 of the housing. It will be noted that the blocker 60 comprises arms 63 and 64 providing a space 65 therebetween. The arms are adapted to lie on opposite sides of the dead bolt 'head 50 as shown in Figure 4. At the bases of the arms .are raised'portions 66 and 67 located so that they are adapted to engage raised portions 58 and 59 atcel'tain positions of adjustment, 'as'illustrated in'Figure 2 A relatively light gage, long compressionjspring 68 is biased between a spring keeper 69a: the inner end 'of the dead bolt head and. a keeper'70 which extends diagonally outwardly from the innerfend portion 61 of the blocker within the space 65. It should be noted that the center line of the spring keeper 69 lies slightly outsideof the center line of the lugs 62. Arranged in this fashion the spring 68 when compressed will bow outwardly into contact with the wall of housing 18,

thereby altering the application of ,spring force to a diagonal direction inwardly. The spring pressure thus applied serves to tilt the'blocker about the mounting of the lugs onthe wall 19 in a counterclockwise direction as viewed in Figure 2 and as viewed also in Figures end 73 by means of which the casing plate can be hooked.

to the inner end 19 of the housing. The casing plate 71 also extends through the inner end 19 in a position separated from the casing plate 72 by the. interposition of the latch bolt shaft 29, the actuator plate 34, and the dead bolt shaft 53, all of which occupy the space between the casing plates and which in assembled condition serve to hold the casing plates apart at the ends which engage the housing. At opposite ends-of the casing plates 71 and 72. suitable rivets 74 are provided to anchor the plates together in separated relationship. Recesses 75 are adapted to receive a post 76 which also forms a portion .of the connecting means 12. The casing plates are further provided with apertures 77 for reception of a hub 78 of the cam 37.

In operation the parts in normal position when the door is opened occupy the positions and relationships illustrated in Figures 2, 3 and 4. As there shown the latch bolt head and dead bolt head are both extended outwardly toward the right. In that position, as best seen in Figure 2, the dead bolt blocker 60 lies substantially In that posilatch bolt head 27 strikes the strike plate, it will move toward the left against the spring 42 until it reaches the conventional opening in the strike plate at which location it will swing back again to outer position as illustrated in Figure 1. As the latch bolt head 27 is being shifted from right to left, it will carry with it the dead bolt. This occurs because wings 52 of the. dead bolt shaft 53 lie behind the latch bolt head 27 so that-the latch bolt head pushes against the wings which in turn engage the dead bolt head 50 causing the dead bolt head to be carried with the latch bolt head toward the left against the compressive tension of the spring 68.

However, when the latch bolt head moves back to its initial position in the conventional recess in the strike plate 16, the dead bolt head will be held depressed in the position shown in Figure 1. Hence, the spring 68 I will remain contracted. Moreover, as the latch and dead bolts move inwardly, the dead latch shaft moves'toward the left. During initial movement the raised portions 66 and 67 remain in engagement with the raised portions 58 and 59 until a flat side so of the latch bolt head 27 ,on account of interposition of the flat face 80 even though the spring 68 is compressed.

'After the door is shut, the latch bolt head 27 moves toward the right but the dead bolt head 50 is held in depressed position, as illustrated in Figure l, by the strike l plate. When the latch bolt head has moved to a position where the flat face 80'pas'ses beyond the free ends of the arm 64, the spring 68 will act against the mid-portion of the blocker 60 causing it to rotate slightly in a counterclockwise direction about the end having the lugs 62 until the blocker comes to rest with the free ends of the arms 64'behind the inside face 43 of the latch bolt head. This is the position illustr'atedlin Figures 1 and 7. In that position should an attempt be made by some instrument manipulated by an unauthorized person to push the latch bolthead 27 toward the left thereby to open the door in the event it were looked through appropriate conventional means, movement of the latch bolt head would be blocked by the blocker.

To open the door the inner operating element 11 can be rotated. Opening could also be accomplished by rotation of the outer operating element 10 if not prevented by some conventional locking device not shown. When the spindle 14 is rotated, the cam 37 is rotated and pushes against one or another of the lugs 36. This causes the actuator plate 34 to be moved from right to left, as viewed in Figure 7, even though the latch bolt head 27 remains stationary. As movement continues, the hooked portion 35, which is wide enough to reach over the raised portions 66 and 67, moves until it slides against the raised POltlOHS,'th616by tending to shift the blocker 60 V in a clockwise direction, as viewed in Figure 7, until it moves out to the position shown in Figure 8. In that position the outer ends of the arms 64 will be clear of the inside face 43 or, in other words, in unblocked position. As the spindle continues to be rotated the hooked portion 35 will pull against the adjacent side of the rectangular opening 30 in the latch bolt shaft and draw the latch bolt head 2'7 from right to left until it clears the aperture in the strike plate. After the door is opened, the spring 42 will return the latch bolt head 27 to its outermost position and at the same time the spring 68 will return the deadbolt head 50 to its outermost position.

It will be noted particularly from an inspection of Figure 7 that when the blocker is in blocking position there is a clearance between the outer ends of the arms 64 and the inner face 43. Hence some movement of the latch bolt head will take place in a direction from right to left until it strikes the blocker. The movement, however, is insufficient to permit disengagement of the latch bolt head from the strike plate. This relationship is of importance when the spindle is rotated inasmuch as it permits sufiicient travel of the hooked portion 35 of the actuator plate to engage the raised portions 66 and 67, thereby to move the blocker out of blocking position before the latch bolt head travels far enough to engage the blocker.

There has accordingly been described herein a dead bolt mechanism of a relatively simple type wherein shafts for the dead bolt, the latch bolt, latch actuator, and blocker all comprise relatively light gage plates positioned side by side, thereby to provide a compact mechanism constructed of stock materials which are relatively inexpensive. The arrangement and relationship is such, however, that the action is positive and secure.

While I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to thedetails disclosed herein but is to be accorded the full scope of the claim so as to embrace any and all equivalent devices.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

In a lock set comprising a latch bolt housing having an inner end wall, sidewall means and an open outer end, a latch bolt member reciprocatably mounted in the housing and protruding from the outer end, a latch bolt head at the outer end of said member and having a shoulder at the inside end, and a plate forming a shaft for the member located in the housing, the combination of a dead bolt mechanism comprising a dead bolt head lying against one side of the latch bolt head and having a parallel path of reciprocation, and a dead locking blocker comprising a plate having an inner end loosely anchored in the inner end wall, means forming an outer end of the blocker lying against the dead bolt head and being tiltable betweena position behind the shoulder on the latch bolt head and a position removed therefrom, a spring keeper on the dead bolt head with the axis thereof parallel to the axis of movement of the dead bolt head and spaced laterally outside the inner end of the blocker, a spring keeper on the blocker extending obliquely outwardly toward the free end of the blocker and intermediate the ends of said blocker, said last keeper being spaced from the dead bolt head, and a separate longitudinally extending compression spring in the space between the keeper on the blocker and the spring keeper on the dead bolt head, said spring having a mid-portion thereof lying against the adjacent side of the housing and a set of bosses respectively on the first identified plate and the blocker normally in engagement when the dead bolt is extended and having positions of disengagement when the dead bolt is depressed relative to the latch bolt whereby said spring is adapted to press axially against the dead bolt and obliquely against said blocker and to move said blocker to a blocking position.

References Cited in the file of this patent UNITED STATES PATENTS 1,876,081 Sehlage Sept. 6, 1932 2,403,597 Hillgren July 9, 1946 2,632,664 Quigley Mar. 24, 1953 2,648,560 Quigley et al. Aug. 11, 1953 2,656,207 Russell et al. Oct. 20, 1953 

